A police source said traces of suspected fire accelerant were found at the scene. The source added that firefighters, thinking the fire had spread in an unusual manner, handed the investigation to police.

“One of the vehicles was suspected to have been torched and fire spread to the other five,” he said.

He said the vehicles’ owners did not know why they had been targeted.

“Over the past few months, the vehicles had been parked there after their daily operation,” the source said. “There was no indication to suggest there were extortion activities in the area.”

He said police were checking whether the minibus owners or drivers had been involved any dispute. By Wednesday afternoon, no one had been arrested.